Patent Document 1 discloses a releasable composition for adhesives, particularly for silicone based adhesives, the composition comprising a copolymer of a monomer mixture as an active ingredient, the monomer mixture comprising:                (1) 50 to 99.5 mass % of a polyfluoroalkyl vinyl monomer represented by the general formula:CnF2n+1(CH2CF2)a(CF2CF2)b(CH2CH2)cOCOCR═CH2                     R: a hydrogen atom or a methyl group            n: an integer of 1 to 6            a: an integer of 1 to 4            b: an integer of 0 to 3            c: an integer of 1 to 3;                        (2) 0.5 to 50 mass % of an organic Si based vinyl monomer containing at least one hydrolyzable group bonded to a Si atom in the molecule; and        (3) 0 to 49 mass % of a non-Si based or organic Si based vinyl monomercopolymerizable with said vinyl monomers, and not containing a hydrolyzable group bonded to a Si atom.        
In this invention, the above vinyl monomer (3), which is a non-fluorine based monomer, is not an essential component (0 mass %). In addition, examples provided as the vinyl monomer (3) are alkyl (meth)acrylate, Si group-containing (meth)acrylate, aromatic vinyl monomers such as styrene, dialkyl esters of unsaturated dicarboxylic acids, maleic acid anhydride, vinyl ether, hydroxyethyl (meth)acrylate, and the like. In practice, the vinyl monomer (3) was not used in the Examples, or methyl ester, n-butyl ester and stearyl ester of methacrylic acid were used as the vinyl monomer (3) in the Examples.
When stearyl ester of methacrylic acid is used, characteristic values are provided such that, compared with when another ester is used or not used, the adhesion is equivalent, the peeling force is smaller at 25° C./one day and 70° C./one day, and the contact angle of decane is larger. However, the results of reproduction tests conducted by the present inventors revealed that although the static contact angles before and after washing with water were satisfactory, the dynamic slip angle after washing with hexadecane was not satisfactory, and additionally that anti-corrosive properties for metal were not satisfactory at all.